42nd Lunar and Planetary Science Conference (2011) 1267.pdf

RECOVERING LOST PIONEER 10 AND 11 IMAGE DATA: A PROJECT UPDATE. T. Stryk, Roane State Community College, Harriman, Tennessee, United States 37849 ([email protected]).

Introduction: Conceived in the late 1960s and include an image of Ganymede from Pioneer 10 and built in the early 1970s, Pioneers 10 and 11 some Pioneer 11 images of Saturn’s rings. No constituted the first attempt to directly explore the Infrared Radiometer data has been found. solar system beyond the asteroid belt. Given that their primary purpose was to be a pathfinder for later missions, they were designed to be as simple as possible, and their instrumentation was primarily geared to making in-situ particle and fields measurements in the asteroid belt and near Jupiter that would ensure the safety of later missions. They were spin-stabilized, which made them well suited for this type of work but ill-suited for remote sensing [1]. Still, both Pioneers carried three remote sensing instruments. The Imaging Photopolarimeter (IPP) Figure 1: Pioneer 11 image D7, showing Io from was a scanning photometer that built up an image by above its north pole. The version on the left is scanning one line at a time, using the spin of the processed from a film print, while the version on the spacecraft to sweep across the target, collecting bot right was made using the original digital data. red and blue channel data. The IPP also had a very low resolution polarimetry channel. The Infrared It is possible that these datasets have not been preserved. In this case, the goal of this project will be Radiometer on each spacecraft made two channel to create a repository of what digital fragments do infrared maps of Jupiter and (in the case of Pioneer exist as well as high quality scans of the best 11) Saturn, while the Ultraviolet Photometer made photographic versions. Still, there is a chance that the low resolution, two channel ultraviolet scans. datasets do still exist, and the most likely place The data from these instruments of significantly appears to be in an archive located at NASA’s Ames higher resolution than anything available at the time Research Center, which served as home to the Pioneer and show the targets at phase angles that were project. Plans have been made to search those previously unseen. Given that the targets include archives in mid-January 2010. The preliminary Jupiter, Io, Saturn, and Titan – worlds that undergo results of this search will be presented in this poster temporal changes visible even at low resolution, along with some results from the data already preserving these datasets for comparison with data recovered. References: from later missions and with ground based [1] Fimmel, R. O. et al. (1980) Pioneer: First to instruments is clearly to be desired. Additionally, Jupiter, Saturn, and Beyond, NASA SP-446. [2] Pioneer 11 obtained relatively high resolution images Graham, F. and B. Hapke. Bulletin of the Amercian of Jupiter from above the North Polar Region, a feat Astronomical Society, 17, 693. that has not been repeated. However, due to the cost at the time of preserving data in digital form (especially at the time of the Jupiter flybys, which occurred in 1973 and 1974, respectively), the only datasets available at the NSSDC and elsewhere are in image form on photographic film except for the low resolution polarization data. While the quality of the film images is generally quite good, not having the digital data prevents the quantitative analysis needed for most scientific purposes. Project Status: The combined datasets include about 300 pairs of images from the Jovian system and about 70 images from Saturn, as well as an unknown number of infrared scans. Only a handful of IPP images have been recovered thus far, including the best image of Io obtained by Pioneer 11 (Fig. 1) and used by Francis Graham in a 1985 paper [2]. Others